1. Field of the Invention
The invention relates to a display system, and more particularly to a display system, which can compensate a threshold voltage of a driving transistor.
2. Description of the Related Art
Because cathode ray tubes (CRTs) are inexpensive and provide high definition, they are utilized extensively in televisions and computers. With technological development, new flat-panel displays have continually been developed. When a larger display panel is required, the weight of the flat-panel display does not substantially change when compared to CRT displays.
Generally, the display panel of the flat-panel display comprises a plurality of pixels. Each pixel comprises a driving transistor and a luminescence element. The driving transistor generates a driving current according to an image signal. The luminescence element displays a corresponding brightness according to the driving current.
However, the driving transistors of the different pixels may comprise different threshold voltages due to manufacturing procedures. When the driving transistors with different threshold voltages receive the same image signal, the driving transistors may generate different driving currents such that the luminescence elements display different brightness.
Additionally, the operation voltage of the luminescence element is drifted because the luminescence element is used for long time. The different luminescence elements may display different brightness when the luminescence elements receive the same driving current. For example, assuming two luminescence elements comprise different operation voltage. If the two luminescence elements receive the same driving current, the brightness of the two luminescence elements are different.